Over the past several decades, Americans have been consuming more and more sugar. This is largely because of an increase in added sugar—sweeteners like sucrose and high-fructose corn syrup added to processed or prepared foods, especially sugar-sweetened beverages and snacks.

The obesity epidemic is the best-recognized consequence of all this added sugar, but researchers are learning that the harmful health effects are not limited to your waistline. Eating or drinking too much added sugar also makes you more likely to develop high blood pressure and diabetes, increasing your risk of developing heart disease.

Evidence is growing that excess sugar may also contribute directly to atherosclerosis, the buildup of fatty plaque on the walls of the arteries that can cause a heart attack or stroke. We already know that eating too many carbohydrates (which includes starch and sugar) raises blood levels of LDL ("bad") cholesterol and lowers HDL ("good") cholesterol. However, no previous studies have examined how added sugar from soft drinks and other sweet snacks affects levels of blood fats that can contribute to atherosclerosis.

What This Study Adds

A recent study, published April 21 in the Journal of the American Medical Association, looked at how added sugar in your diet contributes to unhealthy levels of blood cholesterol and other fats.

The researchers examined results from the National Health and Nutrition Examination Survey (NHANES), a survey of 6,113 American adults. Participants answered questions about all the food and drink they had consumed in the last 24 hours, and gave a blood sample so researchers could measure their cholesterol levels.

On average, people in the study took in 90 grams (21 teaspoons) of added sugar each day, equivalent to 360 calories. The more added sugar a woman consumed, the higher her blood levels of triglycerides (an unhealthy fat) and the lower her levels of HDL ("good") cholesterol. High triglycerides and low HDL cholesterol levels are both linked to a higher risk of developing heart disease.

Eating more sugar was also tied to increased LDL ("bad") cholesterol in men, but this particular link was not seen in women.

What it Means for You

Recommendations to reduce heart disease risk have long emphasized the importance of a diet low in fat and cholesterol. As this study shows, limiting your sugar intake is also an important part of a heart-healthy diet. Just like eating too much fat, added sugar can clog your arteries and contribute to weight gain, diabetes, high blood pressure, and high cholesterol—all strong risk factors for heart disease and stroke.

The American Heart Association recommends that women consume fewer than 100 calories per day of added sugars (about 5% of your total calorie intake for the day). This is equivalent to 25 grams, or about 6 teaspoons, of added sugar a day. The average American eats more than 3 times this amount.

Sugar sweetened beverages (including soft drinks, fruit drinks, energy drinks, and vitamin water drinks) are the number one source of added sugar in the American diet. A single 12-ounce can of soda contains 35 to 38 grams of sugar, which is more than 140% of the recommended intake for an entire day! Other common sources of added sugar include:

Because US food labels contain information only on total sugar, not added sugars, it can sometimes be difficult to determine exactly how much added sugar you are getting. The US Department of Agriculture has published a list of the added sugar content of selected foods, which you can view here: USDA Database for the Added Sugars Content of Selected Foods. If one of the first few items on the ingredient list is sucrose, fructose, cane sugar, beet sugar, or high fructose corn syrup, chances are it contains an unhealthy amount of added sugar.

One simple step that can help you cut down on added sugar is to replace sugar-sweetened beverages with water, which has no calories or additives. For more flavor, coffee and tea are also healthy alternatives—just make sure you do not use sweeteners or creamers that contain sugar. Although diet sodas contain few or no calories, they have little nutritional value and not much is known about how artificial sweeteners affect your long-term health or overall eating habits.